The present invention relates to lock rods and locking mechanisms for releasably locking a toolholder onto a tool support member. It is especially concerned with those lock rods and locking mechanisms which use locking spheres to hold a toolholder and a support member together. Such articles are used in the cutting and shaping of workpieces where it is important that the toolholder be held on the tool support member by the locking mechanism in a rigid manner so that both movement and vibration are minimized during the metalcutting operation.
Many devices in the prior art have proven to be successful in this regard and are exemplified by McCreery U.S. Pat. No. 3,498,653; McCray et al U.S. Pat. No. 4,135,418; Heaton et al U.S. Pat. No. 4,197,771; and Friedline U.S. Pat. No. 4,350,463. The foregoing devices are concerned with the use of ball-like locking elements to hold the shank of a toolholder in the bore of the tool support member. In one prior art design, two ball-like locking elements were releasably driven outwardly to abut with the shank of a toolholder by two inclined ramps on a reciprocally movable lock rod.
However, there is always a need for improved toolholders, support members and locking members that provide a greater degree of rigidity during metalcutting operations such that a single assembly of toolholder, support member and locking mechanism can be used in the widest possible variety of machining operations to provide a given surface finish in a heavier cut or a finer surface finish for a given depth of cut and feed rate.